The present invention relates to materials processing. In particular, the present invention relates to a paper separation and singulation apparatus and method, for the separation of shredded paper and the presenting of the separated paper shreds to a belt conveyor in a single layer fashion for further sorting.
In the sorting of recyclable paper, whether on the basis of color or another property, paper shreds need to be singulated before they can be presented to a sensor for detection of the property of interest. If multiple shreds are conveyed past the sensor, only the top sheet, which is the shred exposed to the sensor, will be detected, and the entire bundle or pile of shreds will be classified according to the top sheet. This will result in both contamination of a superior grade of paper and loss of superior grade paper to an inferior paper grade batch.
In a paper recycling plant a throughput in the order of millions of shreds per hour is essential for economic viability. Such a magnitude is unattainable by manual singulation of shreds. Accordingly, in order to provide effective separation of paper grades at an economically viable rate, automation of the separation process is essential.
The use of automatic singulation in sorting objects has been disclosed in several patents pertaining to the food industry. However, there is presently no effective automatic method of singulating paper shreds for sorting.
The present invention relates to an automatic paper separation apparatus and method which separates compacted paper sheets or shreds from one another for conveyance in separated or singulated form to a sensor for sorting.
The system of the invention comprises a hopper for collection of bundles of paper sheets or shreds and their regulated deposition onto an infeed conveyor. Preferably the conveyor is oriented in such a way that it slopes upwardly at a predetermined angle, to allow the paper shreds to fall from the terminal end of the conveyor at an elevation which is higher than the point of entry, into a paper fluffing apparatus.
The paper fluffing apparatus comprises a batch fluffer, comprising a vessel positioned downstream of the infeed conveyor belt containing a pair of impellers rotating in opposite directions and at selected speeds. The rotation of the impellers subjects compacted bundles of paper shreds to bidirectional forces which overcome both frictional and binding forces within the bundle of shreds, resulting in the separation and singulation of the paper bundles.
In the preferred embodiment the batch fluffer deposits the deaggregated paper sheets or shreds into a surge hopper, which deposits a selected batch volume of deaggregated paper sheets or shreds onto a surge conveyor, also preferably sloping upwardly at a predetermined angle. The surge conveyor feeds the paper sheets or shreds into a drop chute, which further singulates the deaggregated paper shreds by air resistance opposing the acceleration of the paper through the drop chute.
The fluffing apparatus of the invention thus overcomes the coalescence between compacted shreds of paper, separating and substantially singulating the paper shreds for subsequent sorting.
The present invention thus provides a paper separation apparatus for separating bundles of paper sheets or shreds, comprising a receiving hopper for depositing regulated batches of the bundles onto an infeed conveyor, a batch fluffer positioned adjacent to a terminal end of the infeed conveyor, comprising a vessel and a pair of adjacent impellers having blades adapted for rotation at selected speeds, wherein rotation of the impellers subjects the bundles to bidirectional forces which overcome frictional and binding forces within the bundles and separates the paper sheets or shreds into deaggregated paper sheets or shreds.
The present invention further provides a method of separating bundles of paper sheets or shreds, comprising the steps of a, depositing regulated batches of the bundles into a receiving hopper, b. conveying the batches to a fluffing apparatus comprising a vessel and a pair of adjacent impellers having blades adapted for rotation at selected speeds, and c. rotating the impellers to subject the bundles to bidirectional forces which overcome frictional and binding forces within the bundles to deaggregate the paper sheets or shreds.
In further aspects of the apparatus and method of the invention: the batch fluffer deposits the deaggregated paper sheets or shreds into a surge hopper for conveyance to a sorting station; the deaggregated paper sheets or shreds are deposited into a drop chute for deposit onto a sorting stage; the surge hopper deposits the deaggregated paper sheets or shreds onto a surge conveyor for conveyance to the drop chute; the surge conveyor slopes upwardly; the infeed conveyor slopes upwardly; the blades are substantially planar; the impellers are disposed in overlapping relation; the impellers rotate in the same direction; and/or the outlet closure substantially conforms to the rotational profile of the impellers.